One way is to add facts that "map" English atoms to numeric values, and then use these facts to do comparisons, additions, and so on:
numericValue(one, 1).
numericValue(two, 2).
numericValue(three, 3).
numericValue(four, 4).
Now you can do this:
istBiggerThen(XinEng,YinEng) :-
numericValue(XinEng, X),
numericValue(YinEng, Y),
/* The rest of your code goes here */
( X < Y -> true ; false).
Note that numericValue/2
can be used both ways - to convert names to numbers, and to convert numbers to names. For example, you can write a predicate that computes / checks the sum of two atoms spelled out using English names of the corresponding numbers.